Systems and methods for remote utility metering and meter monitoring

ABSTRACT

A system and method for generating and harvesting energy in response to the flow of water through rotating device, such as a nutating or oscillating disk. Mechanical energy from flow of water is converted into electrical energy via an energy conversion unit. For example, the power generation system may be used to power electronic and mechanical devices used in automated meter reading (AMR) systems. The power generator system may recharge a storage circuit that enables long term AMR operations without the need for battery replacement. The power generation system, in various embodiments, can provide additional power for two-way communication and other sensors such as pressure, temperature, water quality and services such as remote shut-off, event-based messaging, and water quality monitoring.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, claims priority to, andincorporates by reference in its entirety, the following, U.S. patentapplication Ser. No. 12/038,151 entitled “System And Methods ForGenerating Power Through The Flow Of Water” filed Feb. 27, 2008, whichis a continuation of U.S. patent application Ser. No. 11/760,200entitled “Systems and Method for Remote Utility Metering and MeterMonitoring,” filed on Jun. 8, 2007, which claims benefit of provisionalapplications 60/811,765 filed Jun. 8, 2006 and 60/869,501 filed Dec. 11,2006, both titled “Systems and Method for Remote Water Metering.”

FIELD OF THE INVENTION

The present invention relates generally to power generation and morespecifically to power generation using the flow of water.

BACKGROUND OF THE INVENTION

Municipal or private water deliver systems usually deliver water from acentral location through a distribution network to water customers on acost per unit of volume basis, most often cost per gallon or cost perliter. In these systems, a water meter is typically placed between acommon water supply pipe and a customer property to measure the amountof water flowing from the supply pipe to the customer. In order to billthe customer for water usage, it is necessary to periodically read themeter to determine the amount of usage over a fixed period of time. Thisprocess is referred to in the industry as metering or meter reading.

Historically, metering has been a labor intensive process, and due tothe manual steps required, one that is prone to error. Some improvementshave been made by utilizing automated meter reading (AMR) techniques tocapture and transmit meter reading information electronically, such asto a technician with a receiving device near the meter or to anotherremote location. However, these automated systems still suffer fromvarious shortcomings including limited battery life, limitedtransmission range, and lack of remote addressability, among others.

SUMMARY OF THE INVENTION

In view of the aforementioned shortcomings of conventional meter readingsystems, at least one embodiment of the invention provides a remotewater meter monitoring system. The remote water meter monitoring systemaccording to this embodiment comprises a water meter body coupling awater supply source to a water customer, a flow sensor contained withinthe water meter body that is configured to measure a bidirectional flowrate of water through the water meter, a power supply system includingat least one battery, at least one capacitor, at least one rectifiercircuit, and a power generator, wherein the power generator is poweredby a flow of water through the water meter body, a controllercommunicatively coupled to the water meter body and power supply system,and at least one antenna connected to the controller.

Another embodiment according to the invention provides a wireless remotewater meter monitoring network. The wireless remote water metermonitoring network according to this embodiment comprises at least onecentral data processing system, at least one bridge devicecommunicatively coupled to the at least one central data processingsystem, and a plurality of network nodes, each network node configuredto perform two-way communication with the at least one bridge device,either directly or through one or more other network nodes, wherein eachnetwork node comprises a water meter housing coupling a water customerwith a water supply line, a flow measurement device in the water meterhousing for measuring a volume of water flowing through the meter, apower supply circuit including at least one power storage device, atleast one capacitive device and a power converter, wherein the powerconverter is powered by water flow through the meter, and acommunication circuit comprising a mesh-type controller and an antenna,wherein the communication circuit is coupled to the flow measurementdevice and the power supply circuit and is adapted to perform two-waycommunication.

Still a further embodiment according to the invention provides a circuitfor a wireless water meter monitoring system. The circuit according tothis embodiment comprises a mechanical energy harnessing sub-circuit forconverting water flow mechanical energy into electrical energycomprising a pair of magnetically coupled rotors driven by water flowand having a plurality of magnets affixed thereto that rotate around aset of coils, thereby inducing a current in the coils, an energy storageand delivery sub-circuit comprising at least one rectifier circuitelectrically coupled to the coils, at least one capacitor charged by theat least one rectifier circuit, at least one battery, and a switch forpermitting the at least one battery to be charged by the at least onecapacitor and for selecting either the at least one capacitor or the atleast one battery to supply continuous power to the circuit and tomanage charging of the at least one battery, a water flow countingsub-circuit comprising a plurality of flux change detectors that detectflux changes caused by a magnet rotating about a shaft driven by a flowsensor of a water flow chamber, a communication sub-circuit electricallycoupled to the energy storage and delivery sub-circuit and the waterflow counting sub-circuit comprising a mesh-type transceiver and anantenna for enabling two-way communication between the wireless watermeter monitoring system and other systems, and a sensor sub-circuitelectrically coupled to the energy storage and delivery sub-circuit andthe communication sub-circuit for recording sensor data and comprisingat least one sensor device.

Still a further embodiment according to the invention provides a powergeneration system. The system according to this embodiment comprises arotating device adapted to rotate in response to flow of water on therotating device, a drive magnet operatively coupled to the rotatingdevice and adapted to rotate in response to the rotating devicerotating, a registration magnet operatively coupled to the drive magnetand adapted to rotate in response to the drive magnet rotating, and agenerator operatively coupled to the registration magnet and adapted toproduce a current in response to the registration magnet rotating.

These and other embodiments and advantages of the present invention willbecome apparent from the following detailed description, taken inconjunction with the accompanying drawings, illustrating by way ofexample the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a typical water utility distributionnetwork beginning with a water utility supply and terminating in aplurality of water consumers.

FIG. 2 is a network diagram of a remote water meter monitoring systemaccording to various embodiments of the invention.

FIG. 3 is a illustration of a water meter pit including a remote watermeter monitoring system according to various embodiments of theinvention.

FIG. 4 is a block circuit diagram of electrical components of a remotewater meter monitoring system according to various embodiments of theinvention.

FIG. 5 is a block diagram of the power conversion circuit for a remotewater meter monitoring system according to various embodiments of theinvention.

FIG. 6 is a flow chart of a method of converting mechanical water flowenergy into electrical energy in a remote water meter monitoring systemaccording to various embodiments of the invention.

FIGS. 7A and 7B are different views of a water measurement headincluding a power conversion generator for a remote water metermonitoring system according to various embodiments of the invention.

FIGS. 8A and 8B are different views of a water chamber and watermeasurement head including a water counting system for a remote watermeter monitoring system according to various embodiments of theinvention.

FIG. 9 is a flow chart of a method for measuring water flow with aremote water meter monitoring system according to various embodiments ofthe invention.

FIG. 10 is a block diagram illustrating the various logic modulesutilized in the remote water meter monitoring system according to thevarious embodiments of the invention.

FIG. 11 is a system block diagram of an example embodiment deployed in aresidential neighborhood.

FIG. 12 is another system block diagram of an example embodiment.

FIG. 13 is a system block diagram including photographs of componentelements of an example embodiment.

FIGS. 14 and 15 are photographs of example wireless motes suitable foruse in various embodiments.

FIG. 16 is a component block diagram of an example embodiment of asensor and wireless mote assembly.

FIG. 17 is a circuit block diagram of an example embodiment of sensorand wireless mote assembly.

FIG. 18 is a system architecture of a power generator portion of anexample embodiment of sensor and wireless mote assembly.

FIG. 19 is an illustration of the relationship between magnetic fieldsand electrical coils implemented within a generator of an exampleembodiment of sensor and wireless mote assembly.

FIG. 20 includes two elevation views and a cross section views of therotor and stator portions of a generator of an example embodiment ofsensor and wireless mote assembly.

FIG. 21 is a cross sectional view of an assembled generator of anexample embodiment of sensor and wireless mote assembly.

FIG. 22 is a photograph of a prototype stator and rotor assembly of thegenerator illustrated in FIG. 20.

FIG. 23 includes elevation view of the top and bottom rotors of agenerator of an example embodiment of sensor and wireless mote assembly.

FIG. 24 is a cross sectional view of the stator and rotor assemblyillustrated in FIG. 20 show lines of magnetic flux between the rotorsillustrated in FIG. 23.

FIG. 25 is a photograph of a prototype rotor of the generator illustratein FIG. 20.

FIG. 26 is a photograph of a prototype stator of the generatorillustrate in FIG. 20.

FIG. 27 is an elevation view of the stator of the generator illustratedin FIG. 20 provided for comparison to the photograph shown in FIG. 26.

FIG. 28 is a photograph of a housing into which the rotor and statorassembly illustrated in FIGS. 20-26 may be fitted.

FIG. 29 is a schematic diagram showing the relationship of rotor magnetsto stator coils of the rotor and stator assembly illustrated in FIGS.20-26.

FIG. 30 is a coil wiring diagram for the stator portion of the rotor andstator assembly illustrated in FIGS. 20-26.

FIG. 31 is a circuit diagram of an example rectifier useable in anexample embodiment of a generator of an example embodiment of sensor andwireless mote assembly.

FIG. 32 includes two tables showing test results of two prototypegenerators.

FIG. 33 is a photograph of a Hall effect sensor for use in an embodimentsensor.

FIG. 34 is a photograph of two Hall effect sensors positioned on ahousing for use as a water meter sensor.

FIG. 35 is a logic table for interpreting signals received from Halleffect sensors configured as shown in FIG. 34.

FIG. 36 is a process flow diagram of a method of operating an embodimentsensor and wireless mote assembly.

These and other embodiments and advantages of the present invention willbecome apparent from the following detailed description, taken inconjunction with the accompanying drawings, illustrating by way ofexample the principles of the invention.

DETAILED DESCRIPTION

The following description is intended to convey a thorough understandingof the embodiments described by providing a number of specificembodiments and details involving systems and methods for remote watermeter monitoring. It should be appreciated, however, that the presentinvention is not limited to these specific embodiments and details,which are exemplary only. It is further understood that one possessingordinary skill in the art, in light of known systems and methods, wouldappreciate the use of the invention for its intended purposes andbenefits in any number of alternative embodiments, depending uponspecific design and other needs.

Referring now to FIG. 1, this Figure is an illustration of a typicalwater utility distribution network beginning with a water utility supplyand terminating in a plurality of water consumers. The network 100begins with a water service provider 110 such as a public water utilityor commercial water service provider. As is known in the art, the waterservice provider 110 may comprise a water reservoir and various waterquality processing elements that condition the water prior to beingpiped to consumers. One or more water supply pipes 115 flow out of thewater service provider 110 creating a water distribution network. Theone or more water supply pipes 115 provide water to a plurality of waterconsumers 130. For ease of illustration, the water consumers 130 areillustrated as residential units. However, the water consumers may bebusinesses, factories, irrigations systems, or other entities thatreceive water from the water service provider 110.

Each water consumer 130 is coupled to the at least one water supply line115 by a water meter 120. The water meter provides a physicalinterconnection between consumers 130 and the water supply line 115. Thewater meter 120 also measures the amount of water flowing to eachconsumer from the supply line 115. This data is typically used to billthe customer for their water consumption over a specified time periodsuch as a month or quarter. The water meter 120 includes a dial, gauge,or other display that quantifies the amount of water that has passedthrough the meter into a number of gallons. As discussed above, in orderto bill customers for their water consumption, the water utility usuallysends a meter reader out to the read the number from each water meter120. The previous reading is subtracted from this number and thecorresponding numbers of gallons consumed are billed to the customer.

A conventional water meter usually includes a water chamber having awater input, a water output, and a water flow measuring device, such asa rotating, notating or oscillating disk, or other flow meter, thatdrives the gauge on the top surface of the meter. The meter chamber isusually made of a non-corrosive metal such as copper or bronze. Also,the pipe connecting the meter chamber usually includes a manual shut offvalve that can be manually engaged to prevent water from flowing fromthe supply pipe 115 to the consumer 130 through the meter 120, tofacilitate the repair or replacement of the water meter or otherelements within the customer premises.

FIG. 2 is a network diagram of a remote water meter monitoring systemaccording to various embodiments of the invention. The network 200 shownin FIG. 2 is similar to that of FIG. 1 in that a water service provider110 is coupled to a plurality of water consumers via a water supply pipe115. However, in the network 200 of FIG. 2, each water consumer isrepresented by a wireless communication based network node 230. Forpurposes of this disclosure and claims the network node 230 compriseswith physical water meter housing as well as the power, control andcommunications circuitry. Water enters each of the consumer premisesfrom the supply line 115 via the a water meter housing of each node 230.Each node 230 also comprises a wireless ad hoc network transceiver unitthat is operable to wirelessly transmit water meter reading informationto a bridge device 210, which, in turn, passes the information to one ormore server computer systems associated with the water service provider110. In various embodiments this information may be accessible over awide area network, such as the Internet, by anyone having appropriateaccess credentials with a network browser, such as an Internet webbrowser.

The bridge device 210 may communicate with the one or more servercomputer systems (not shown) via a land line, a wireless cellularconnection, a wireless 802.1 1× connection, WiFi, (including municipalWiFi and WiMAX), fiber optic connection, a cable connection, atwisted-pair copper phone line, a satellite connection, other known orpreviously unknown communications medium, or combinations of any ofthese. The specific communications medium between the bridge device 210and the one or more server computers is not critical to the variousembodiments of the invention.

With continued reference to FIG. 2, each node 230 acts as both a sensorand a data router. Each node may transmit a signal directly to thebridge device 210, or pass the information through one or more othernetwork nodes 230. This feature of self-forming, self-healing ad hocnetworks is known in the art and particularly advantageous to thevarious embodiments of the invention because the physical environment ofthe network 200 may change due to the presence of cars, trucks and othertemporary obstructions within the network 200, affecting the propagationof radio frequency (RF) signals between nodes or between a node and thebridge device 210.

It should be appreciated that each network node 230 may, up loadinformation to the bridge 210 as well as receive information and/orinstructions from the bridge 210. That is, a network node 230 may repeata signal destined for the bridge device 210 or one that is destined foranother node 230. Techniques and algorithms for optimizing ad hoc ormesh networks are well known in the art. The various embodiments of theinvention do not depend on any particular type or brand of ad hoc ormesh network hardware.

As will be discussed in greater detail herein, in the network 200, eachnetwork node 230 may upload information according to a predeterminedschedule, such as, for example, once every hour. Also, an upload signalmay be sent on demand, from the bridge device 210 to each of the networknodes 230 causing them to perform a specified task or to uploadinformation to the bridge device 210.

It should be appreciated that this information may include current watermeter reading information as well as other information associated withthe node, such as, for example, current state, power information,temperature information, water pressure information, backflowindication, and/or any other sensor-based information from one or moreelectronic sensors in communication with the network node 230, as willbe discussed in greater detail herein.

Referring now to FIG. 3, this Figure is an illustration of a water meterpit including a remote water meter monitoring system according tovarious embodiments of the invention. In a conventional system, a waterpit typically includes a water meter, that is comprised of a waterchamber and a water measurement head that is equipped with a gauge orother meter on the top and a manually shut off valve coupling the watersupply line to the customer premises. In the system depicted in FIG. 3,the conventional water measurement head has been replaced with a newwater measurement head, 265, according to the various embodiments of theinvention. The water meter 250 may include a water chamber 260 throughwhich water flow passes from the water supply 115 to the consumer watersystem 215, and a water measurement head 265 that attaches to the waterchamber 260. The measurement head 265 may also include a water countingmodule 270 having a flow meter, a power conversion module 280 and acontrol module 300. The control module 300 may also include a wirelineconnection 315 to an antenna 320 coupled to the meter pit cover 245. Invarious embodiments, the meter pit cover 245 may comprise a metal platewith a through-hole near the center allowing the antenna 320 to contactthe wire 315. The antenna 320 may be encased in resin or plastic, orother material, in order to prevent breakage when the meter pit cover245 is stepped on or driven over with a bicycle, car, or other vehicle.The fact that the meter pit cover 245 is a relatively massive,conductive object, it serves as an ideal ground plane for the antennathereby increasing the range and performance of the wireless networkaccording to the various embodiments of the invention. This isparticularly advantageous for retrofitting the system according to thevarious embodiments of the invention to existing water supply networks.The only required modification to the meter pit cover 245 is making athrough-hole and attaching the antenna 320.

In various embodiments, a separate manual shut-off valve 116 may beplaced or left in the meter pit 240 to permit manual shut off of thewater supply using conventional techniques. Alternatively, and/or incombination therewith, an electronically controllable shut off valve maybe incorporated into the water chamber 260, or attached pipe, 215,thereby permitting remote water shut off, as will be discussed ingreater detail herein. This electronically controllable shut off valvemay comprise a spring loaded valve. In various embodiments, this valvemay be manually tensioned into an open position with an external switchor valve control. A solenoid may be used to release the shut off valvebased on a remote command received by the control module 300 of themeter system 250. This may require the water service provider to send atechnician or other person out to the customer premises to return theshut off valve to the pre-tensioned, open position, such as, forexample, after the consumer's water service account has been madecurrent.

In the water meter, 250, according to FIG. 3, water flowing through thewater chamber 260 may be counted by the water counting module 270 usinga nutating valve assembly or other water volume measuring device thatpasses a known volume of water with each complete rotation, as isdiscussed in greater detail in the context of FIGS. 8 and 9. It shouldbe appreciated that the various embodiments of the invention are notreliant on the particular type of water volume measuring device that isutilized. Several such mechanical devices are known in the art.

Also, in the water meter 250, mechanical energy of the pressurized waterpassing through the water chamber 260, may be harnessed by the powerconversion module 280 to provide electrical power for all the metersystem components in the measurement head 265, as is discussed ingreater detail in the context of FIGS. 4-6.

Referring now to FIG. 4, this Figure is a block circuit diagram ofelectrical components of a remote water meter monitoring systemaccording to various embodiments of the invention. The electricalcomponents include a power conversion module 280. The power conversionmodule 280 includes a mechanical energy converter 287 located in thewater chamber 260. The energy converter 287 may include an impellor,nutating disk, blade assembly or other surface area device rotatingabout a drive shaft to which torque is imparted by the flow of water.This rotating shaft may be used to energize one or more components in apower converter and supply module 290. The power converter and supply290 may include one or more capacitors, one or more batteries, andcontrol logic and/or switches for supplying system power to variouscomponents of the remote water meter monitoring system according to thevarious embodiments of the invention.

The power converter and supply 290 may output power to a power bus 295.The power bus 295 may supply power to the control module 300 as well asone or more sensors 289-1, 289-2. The power bus 295 may also supplypower to a solenoid or. other actuator of an electronic shut off valve325.

The control module 300 may include a transmitter and receiver(transceiver) 305, a microprocessor 310 and one or more memorystructures (not shown) storing a control program executed by the controlmodule 300 as well as historical data from the water counting module 270and sensors 289-1, 289-2, . . . , 289-N. The sensors 289-1, 289-2, . . ., 289-N, may comprise water pressure sensors, temperature sensors, waterquality sensors, or other sensors. Alternatively, or in combination, thesensors 289-1, 289-2, . . . , 289-N may be incorporated into a singlesensor module, such as a board or chip-based sensor lab that performs avariety of diagnostic tests on the water. The sensor information may becommunicated periodically or in real time to the control module 300 viacommunication bus 335, such as universal asynchronousreceiver/transmitter (UART), serial peripheral interface (SPI) bus,inter-integrated circuit (I²C), 1-Wire or USB. Also, the control module300 may poll the one or more sensors 289-1, 289-2, . . . , 289-Nperiodically or on demand to obtain information corresponding to waterconditions, current or past. The water counting module 270 may beelectrically coupled to the power bus 295 and communicatively coupled tothe control module 300 via the data bus 335.

Referring now to FIG. 5, this Figure is a block diagram of a powerconversion circuit of a power conversion module for a remote water metermonitoring system according to various embodiments of the invention. Asdiscussed briefly in the context of FIG. 4, the power conversion circuitmay include an energy converter 287 driven by an mechanical energy ofwater flow. The energy converter 287 may convert the mechanical energyof the rotating shaft into electrical energy as discussed in greaterdetail in the context of FIGS. 6 and 7. After conversion by rectifier288, the electrical energy generated by the energy converter 287 maycharge a capacitor 292 of the power converter and storage module 290,which may in turn charge a battery 294. A switch 296 may select eitherthe capacitor 292 or the battery 294 to supply output power, such as tothe power supply bus 295 shown in FIG. 4. In various embodiments, theswitch 296 may include decision logic for selecting either the capacitor292 or the battery 294 based on a current state of either or bothdevices, or in accordance with a predetermine power management schemestored in a memory device of the switch 296 or another memory structureexternal to the switch 296. In various embodiments, by placing thecapacitor 292 between the energy converter 287 and the battery 294, thenumber of charge cycles of the battery 294 may be significantly reducedover direct charging techniques, thereby increasing the effective lifeof the system. Also, the switch 296 may help to insure that the battery294 is charged by the capacitor 292 only after the battery 294 has beenfully discharged to avoid battery memory problems and increase theusable life of the battery 294.

FIG. 6 is a flow chart of a method of converting mechanical water flowenergy into electrical energy in a remote water meter monitoring systemaccording to various embodiments of the invention. The method begins inblock 400 and proceeds to block 405 where water flowing through themeter's water chamber rotates a turbine, impeller, blade and shaftassembly, or other mechanism that rotates with the flow of water, orcauses a nutating disk assembly or other volume measuring assembly to beactuated. The mechanical energy created in block 405, in the form of theshaft rotation, is used to drive a drive magnet, in block 410. In block415, the rotation of the drive magnet creates a time varying magneticflux density that drives a registration magnet, which, in variousembodiments, may be located above the portion of the meter assemblythrough which water is flowing. In block 420, the rotation of theregistration magnet may drive the generator, either directly, such asvia a drive shaft, or indirectly, through a mechanical gear assembly. Invarious embodiments, this may comprise spinning a pair of magneticallycoupled rotors around a set of coils as discussed in the context ofFIGS. 7A and 7B. The time changing magnetic flux caused by the rotationof the magnetically coupled rotors induces a time varying current in thecoils generating an electrical current. In block 425, the currentcreated in block 420 is output to a charge storage circuit. In variousembodiments, this may comprise communicating the current to the input ofa rectifier circuit that converts alternating current (AC) to directcurrent (DC) that can be used to create a stored charge in thecapacitor. This stored charge can be used to provide line power to theremote meter monitoring system. This stored charge can also be used tocharge the battery of the power conversion module.

FIGS. 7A and 7B are different views of a water meter, including a powerconversion generator for a remote water meter monitoring systemaccording to various embodiments of the invention. FIG. 7A shows acut-away view of the water meter system 250, including the energyconverter 287. Water enters the water chamber 260 in the directionindicated by the arrow 115A. The force of this water contacts the energyconverter 287, which, in this example, includes a nutating diskassembly. It should be appreciated that another water volume measuringdevice may be utilized to measure the flow rate. In the exemplaryembodiment depicted in FIG. 7A, the nutating disk's motion drives adrive magnet 281 via a drive shaft 281A in the water chamber 260. Inaddition to providing a magnetic flux change detectable by the watercounting module 270, the drive magnet 281 drives a registration magnet282, located in the measurement head 265, via magnetic conduction. Theregistration magnet 282 rotates about an is 282A, which also controlsthe rotation of the rotor elements 283 of the power conversion module280. The power conversion module 280, also referred to herein as angenerator, may comprise a pair of magnetically coupled rotors 283 thatface each other having magnetic plates 284 affixed thereto, the rotationof which is driven by the registration magnet, either directly, or via amechanical gear assembly.

In various embodiments, such as is shown in the context of FIG. 7B, eachrotor 283 may have a number of magnets, or magnetic plates 284 affixedthereto. For illustration purposes only, eight magnets are shown in FIG.7B. However, it should be appreciated that more or fewer magnets maybeused with the various embodiments of the invention. Also, a magneticdisk with one or more magnetic pole pairs may be utilized instead of therotor 283 shown in FIG. 7B, without departing from the spirit or scopeof the invention. In fact, the various embodiments of the invention arenot tied to any particular rotor design. In the example of FIGS. 7A and7B, the magnets 284 are coupled to one another with North-South polesfacing each on the respective upper and lower rotors 283. Between therotors 283 is a set of fixed conductive coils 285. In variousembodiments a number of multi-turn coils may be suspended between themagnetically coupled rotors. Also, the coils 285 may be oriented so thatwhen the rotors 283 rotate, the direction of the magnetic field passesthrough the center is of each coil, thereby inducing a maximum currentin each coil 285. However, it should be appreciated that otherorientations may be utilized as well. Furthermore, the number of coilsthat may be utilized is not critical to the various embodiments of theinvention.

With continued reference to FIG. 7A, as the water flow drives therotation device, this in turn rotates the drive shaft 281A. Rotation ofthe drive shaft causes the drive magnet 281 to rotate, either directly,or indirectly, through a gear assembly. Rotation of the drive magnet281, in turn, may cause a registration magnet 282 to rotate via magneticconduction. The registration magnet may rotate about its own shaft 282A.Rotation of the shaft 282A may cause a pair of magnetically coupledrotors 283 to rotate, thereby inducing a current in a series of coils285 suspended between the facing rotors 283. This current may have agenerally sinusoidal magnitude over time due to the changing pattern ofmagnetic flux density over the rotors' 283 rotation. The outputs of thecoils 285 are supplied to the input of the power conversion and supplymodule 290. For example, the output of the coils 285 may be rectifiedand used to charge a capacitor such as the capacitor 292 in FIG. 5.

Referring now to FIGS. 8A and 8B, these Figures are different views of awater chamber and water measurement head including a water countingsystem for a remote water meter monitoring system according to variousembodiments of the invention. The water counting module 270 is comprisedof a water counting mechanism. The water counting mechanism isconfigured to quantify motion of a volumetric element to a specifiedvolume of water. This in turn can be used to determine water consumptionthrough the meter. One example of such a volumetric element is anutating disk based system, such as that depicted in FIG. 8A. It shouldbe appreciated that other mechanical volume meters may be used withoutdeparting from the spirit or scope of the invention. In the example ofFIG. 8A, water entering the water chamber 260 passes through a diskchamber 271. A nutating disk 272 wobbles about a ball and cradle typejoint 273 having a center is 274. The movement of the center is 274causes a shaft 281A to drive a magnet 281. Thus, each rotation of themagnet 281 may be correlated mathematically to the passage of a discreteand known volume of water. A plurality of magnetic flux detectors 277A,277B, 277C, such as a Hall effect sensors or other sensors, attached tothe cover 278 may be used to “count” the number of rotations of thedrive magnet 281. Using a known conversion parameter, these counts maybe used to determine flow rate and therefore water consumption.

In the exemplary system shown in FIG. 8, three sensors 277A, 277B, and277C are used. In: various embodiments, a first sensor 277A may be usedto selectively wake up a controller in the control module 300 from asleep or low power state. For example, the CPU of the control module maydefault to a sleep state to reduce power consumption. When the firstsensor 277A senses a magnetic flux change caused by rotation of thedrive magnet 281, it may send a signal to wake up the processor of thecontrol module via an interrupt pin on the CPU, causing the CPU toprepare to begin recording water consumption.

The second sensor 277E may be used to count the number of rotations ofthe magnet that occur. A parameter may be stored in advance in thecontroller or elsewhere correlating the number of rotations per gallonof water flow. Thus, in various embodiments, each count by the sensor277B sends a signal to the control module. Every N of these signals maycause the microprocessor to increment a water usage variable stored inmemory to reflect the increased water consumption.

In various embodiments, a third sensor 277C may be incorporated topermit the system to detect a backflow condition, that is, water flowinginto the supply pipe from a customer premises. This may be indicative ofincorrectly connected plumbing lines within the premises, an attempt tointroduce contaminants into the water supply, or even a break in thewater supply line. By positioning the third sensor 277C within apredetermined number of radians with respect to the second sensor 277B,such as, for example, between π/4 and π/2 radians, it may be possible todetermine the direction of water flow through the chamber 271. This maybe done by comparing the measured north-south pole transitions from thesecond sensor 277B and the third sensor 277C for a given time period.The pattern will be different in the case of reverse motion of themagnet causing the control module to determine that back flow isoccurring. The control module may increment a different counter torecord backflow. Also, backflow in excess of a predetermined amount maycause a shut off valve to be automatically engaged and/or a signal to besent to the bridge device notifying the water supplier of the existenceof the backflow condition.

It should be appreciated that the particular type of water countingmechanism is not critical to the various embodiments of the invention.Various different sensor types may be used in conjunction withmechanical flow control devices such as a nutating disk to count thevolume of water flowing through the water chamber 260, with a generalgoal of reducing and minimizing current drawn by the sensors.

Referring now to FIG. 9, this Figure is a flow chart of a method formeasuring water flow with a remote water meter monitoring systemaccording to various embodiments of the invention. The method begins inblock 500 and proceeds to block 505 where water flows into the waterflow chamber of the water meter. Generally, such flows are driven by arelease of water in a customer premises such as by turning on a faucet.

In block 510, the water flowing into the water flow chamber must passthrough a rotating, nutating, or oscillating disk or other flowmeasuring mechanism, or flow meter, causing a shaft to rotate inaccordance with a cycle of the disk. As discussed above in the contextof FIG. 8A, in one nutation cycle a known volume of water has flowedthrough the water meter. Next, in block 515, the rotation of thenutation disk, or other flow sensor causes a drive shaft to turn whichin turn causes a drive magnet to rotate due to mechanical coupling ofthe flow sensor to the drive magnet.

The rotation of the drive magnet generates a time changing magneticfield, that is, a change in flux density over time. In block 520, asensor, such as a Hall effect sensor, or other flux change sensor,detects this changing flux density caused by the drive magnet'srotation. In various embodiments a non-magnetic material will be usedfor the water chamber to enable the flux change to be detected throughthe sealed water chamber. In block 525, the sensor sends a wake-upsignal to a control module to “wake up” and begin recording water flow.In block 530, another sensor counts the magnetic pole changes caused bythe rotating magnet and sends a count signal to the control module. Inblock 535, based on a look-up value corresponding to the parameters ofthe meter, the control module calculates a flow rate based on the numberof mutation cycles. In block 540, a water usage variable is incrementedfor each unit of flow, such as, for example, for each gallon.

Referring now to FIG. 10, this Figure is a block diagram illustratingthe various logic modules utilized in the remote water meter monitoringsystem according to the various embodiments of the invention. The system600 comprises various modules which may provide functionality forfacilitating rewards-based investments over a communication network.

In the example of FIG. 10, a control module 610, a communication module620, a water flow module 630, a sensor module 640 and a memory module650 are shown. It should be appreciated that each module 610, 620, 630,640, and 650 may be configured as a software application executing oncomputer hardware, an application specific integrated circuit (ASIC), acombination of hardware and software, combinations of these, or othersuitable configuration. In commercially available mesh network nodes,single package solutions are available that includes a programmablemicroprocessor and a radio transceiver based on one or morecommunications protocols, such as, but not limited to, for example, theIEEE 802.15.4 standard for wireless personal area networks (WPANs). Itshould also be appreciated that one or more of modules 610, 620, 630,640, and 650 may be combined or broken into multiple additional modules.Furthermore, modules different than the exemplary ones depicted in FIG.10 may be used with the various embodiments of the invention.

The control module 610 may comprise an embedded microprocessor, DSP, orother processor, or even a real-time kernel of an embedded operatingsystem. The control module 610 may be programmed with an instruction settailored to the specific application of remote water meter monitoring.For example, the control module 610 may be programmed with a set ofinstructions that can be received remotely, as well as a set ofmanufacturer/integrator defined parameters, including a schedule ofoperator, e.g., uploading data every hour. The control module may alsoinclude a system clock.

The communication module 620 may comprise a two-way radio (transceiver)configured to communicate using one or more wireless communicationsprotocols. The communication protocol may also store mesh networkselection algorithms for determining an optimal network path. This typeof information is typically programmed by the manufacturer of thetransceiver. The communication module 620 may permit two-waycommunication from the system 600 to/from a bridge device, eitherdirectly, or through one or more other such systems.

The counting module 630 may receive count signals from one or moresensors or detectors indicative of a water flow through the water flowchamber. The counting module 630 may convert these count signals, basedon a stored value correlating the count signals to a particular volumeof water, into a flow rate. This flow rate may then be used to incrementa running total of water consumption in a particular billing unit, suchas in gallons. The counting module 630 may store and increment thisvalue in the memory module 640. The memory module may consist of arelatively small amount of non-volatile memory that is used to storewater consumption information as well as information from other sensorsand components.

The sensor module 650 may receive information from one or moretransducers or other sensors that are capable of sending electricalsignals corresponding to physical phenomena. The sensor module 650 mayinclude a standard or non-standard data bus connected to sensor busadapted to interface with one or more sensors. For example, a pressuresensor may sense ambient water pressure in the pressure chamber andconvert this information to an electrical signal that is received by thesensor module 650. The sensor module 650 may poll the sensors to provideinformation periodically. Alternatively, the sensors may send theinformation to the sensor module 650 periodically. The sensor module 650may store this sensor information in the memory module 640 so that itcan be uploaded by the control module 610 via the communication module620 in accordance with an upload schedule or on demand. The sensormodule 650 may communicate with individual sensors, such as sensors forpressure, temperature, water quality, etc. Alternatively, the sensormodule 650 may communicate with an integrated sensor, such as alab-on-a-chip or lab-on-a-board that is capable of performing aplurality of different water quality tests in real or near real time.

The various embodiments disclosed herein may provide a remote watermeter monitoring system that reduces costs and increases accuracy ofwater meter reading. Also, various embodiments may provide access towater meter information remotely via network-based interface such as anycomputing device executing a network browser such as an Internet webbrowser. Further, various embodiments may provide additional servicessuch as remote water shut off, event-based messaging, back flowdetection, and water quality monitoring. For example, the control modulemay be programmed to upload a message when more than a pre-determinedamount of water has flowed through the meter, indicating a potentialleak situation. This may cause a message to be sent to the watercustomer based on previously specified contact information.Additionally, the customer may be able to access his/her own account viaa server system maintained by the water service provider in order toremotely monitor past and current water usage conditions at thecustomer's premises. Also, various embodiments may harness mechanicalenergy from water flowing through the meter to generate power. Thispower generation may eliminate the need for redundant power systems orline power. Furthermore, by using the capacitor as the primary powersource and managing the charging cycles of the system batteries, mayextend the life of the system, eliminate the need for batteryreplacement, and provide additional power for the other sensorsdiscussed herein. A particular embodiment is now described withreference to FIG. 11 through FIG. 36.

FIG. 11 shows a typical “cluster” of residences 400 each having anembodiment of a wireless reporting water meter referred to herein as“METER Mote” 401. As FIG. 11 shows, each METER Mote 401 includes asensor 402 and a wireless mote 401. The METER Motes can collect data attheir individual locations and route the data back either directly to acentral collection point 405, referred to herein as a collector or a“StarGate” or through another METER Mote wireless mote 404. The StarGatecollector 405 collects the data from each METER Mote 401 in the clusterand has its own address within the communications system. The StarGate405 can connect to a Communications network, a WiFi network or acellular system. As FIG. 11 illustrates, the StarGate 405 can bepositioned on a utility pole within a neighborhood.

The METER Mote System may be comprised of six main components: a FlowMeasuring Element 402, a Wireless Sensor Network Mote 404, a flowisolation valve system 115, 116, a water pressure/quality detector (notshown), an Antenna System 315 and the Collector 405. A METER Moteregistration device can replace the “traditional” registration devicethat normally would house the totalizer and automatic meter readingcircuitry (AMR) if utilized. The METER Mote registration device mayconsist of the Wireless Sensor Network Mote, measuring circuitry and thewater powered charging circuit. The wireless registration device may fitinside the housing of a traditional water meter head, such as the BadgerMeter Model 25.

The wireless motes 404 use mesh networking technology to form a wirelesssensor network of METER Motes 401, or a sensor cluster 412 asillustrated in FIG. 12. Each sensor cluster 412 connects to a collector405 to transmit data from the members of the cluster. Communicationbetween Motes 401 and the collector 405 is through a process calledmultihop mesh networking which is a self-organizing and self-healingcommunication protocol. Multihop mesh networking enables powermanagement and exploits multipath reflections, as experienced inneighborhood deployments, for better RF coverage. Data delivered to thecollector 405 can then be accessed via Ethernet, WiFi or cellular datanetwork connections via the Internet. The collector 405 can send datadirectly to an operations base. So configured, the system can provideusers with real time access to any meter in the network andcommunication can be two-way.

The wireless mote 404 in both the METER Mote sensors 401 and thecollector 405 may be a MICA2 Dot manufactured by Crossbow Technologiesas illustrated in FIG. 13. As another example, the wireless mote 404 maybe MICA2 Mote developed by Crossbow Technologies as was used in aprototype system. Illustrated in FIG. 14, the MICA2 has a low cost, lowpowered on-board processor, 916 MHz radio and sensor board that cansupport water flow measurement, backflow detection and water pressureinformation A water powered charging circuit (described more fullybelow) can replace the battery package shown in FIG. 14. The MICA2 alsohas over 500 k bytes of on-board memory, allowing the storage ofmultiple water flow and sensor reads. The METER Mote can store waterflow and sensor reads in non-volatile memory, ensuring no loss of datain the event of power loss. Wireless motes 404 are small in size, asillustrated by the MICA2 Dot mote shown next to a quarter in FIG. 15.The METER Mote embodiment may use an off-the-shelf product from CrossbowTechnologies called the StarGate as the Collector 405. The Collector'srole is to act as a bridge between the individual METER Motes 401 andthe outside world. The StarGate can be tasked by a utility company tocollect data from its respective METER Motes 401 and route the data backvia a secure communications connection. The Collector 405 can be mountednext to a cable junction box, allowing easy access to a communicationsnetwork.

The METER Mote System prototype can use an off-the-shelf positivedisplacement disk type Flow Measuring Element called a “nutating” disk.A nutating disk displaces a specific volume of water at each rotationcaused by the water pressure. Each “nutation” drives an output magnetthat allows the accurate measurement of water flow. Current water metersmeasure the number of nutations by magnetically engaging a magnet in theRegistration Device, which is physically separated from the FlowMeasuring Element, to drive the gear train of a register.

In addition to using the nutating action to measure water flow, theMETER Mote 401 can scavenge power for the on-board electronics byelectromagnetic induction. As illustrated in FIG. 16, the METER Mote 401embodiment includes an inline micro-turbine or nutating disk C thatdrives a generator the power from which is controlled and stored in apower supply, battery and capacitor circuit B and used to power thewireless mote electronics A. As illustrated in FIG. 17, mechanicalenergy from water flow is captured by an energy harvesting and storageunit 440 in order to provide a voltage source Vcc for sensors 405 andthe wireless mote 404. A key advantage of the METER Mote embodiment isthe ability to power itself from the water pressure in the residentialwater system. In addition, the ability to recharge a storage circuitfrom water flow can supports future expansion and allow for duty cyclegrowth.

The METER Mote embodiment utilizes a unique charging circuit that usessuper capacitors as the primary power source and a lithium battery asthe secondary power source. This design is needed as current batterytechnology supports only 300 to 500 recharge cycles. This limitationreduces effective battery lifetime, meaning that batteries cannot beused as the sole power source. Capacitor have virtually unlimitedrecharge cycle life and are ideal for frequent “pulsing” applications,such as residential water flow. Assuming a water usage duty cycle of 20%and a METER Mote duty cycle of 1%, calculations indicate a 1/10 Wattpower output from the water powered charging circuit can be enough toprovide power to the METER Mote embodiment for approximately 20 years.

The water powered charging circuit design, which is illustrated in FIG.18, is simplified by allowing the on-board processor 420 of the wirelessmote 404 to have complete control over buffer selection and charging,directing the METER Mote 401 via switch 448 to draw power from the supercapacitor 442 first thereby minimizing the charge cycles the battery 446is subjected to. This architecture supports future sophisticated powermanagement schemes.

Mechanical energy from the flow of water is converted into electricalenergy in the METER Mote embodiment using a unique generator design,details of which are illustrated in FIGS. 19-32. Referring to FIG. 19, amagnetic field is caused to rotate by magnetically coupling a rotor to adrive shaft connected to the a micro-turbine of nutating disk C. As themagnetic field rotates past coils, electricity is caused to flow firstin one direction (Step #2) and then in the opposite direction (Step #4).

Details of the generator assembly 462 are illustrated in FIG. 20 whichshows a cross section of the assembly 462 and elevation views of therotors 464 and stator 468. The generator assembly is a miniature axialflux permanent magnet generator (AFPMG). It includes a single stator 468which is configured as a disk including eight coils 470 wired in asingle phase and approximately equally spaced about the disc. The statoris positioned between two rotors 464 each including eight permanent ½inch diameter permanent magnets 466. In an embodiment the permanentmagnets are NdFeB Grade 42 permanent magnets 0.5 inch in diameter and0.125 inch high. The rotors are magnetically conductive plates, such assilicon steel (electrical steel). The magnets on the two rotors 464 areconfigured so the magnets 466 on the two rotors are in attractingpositions. The rotors 464 are positioned in close proximity and oneither side of the stator 468. In an embodiment, the rotors 464 aresuspended just 0.25 inch apart when assembled and are approximately 2inches in diameter.

The rotors 464 are suspended on a drive shaft 476 which is coupled to afirst drive magnet 474 as illustrated in FIG. 21. The first drive magnet474 is magnetically coupled to a second drive magnet 472 on the wet sideof a housing membrane 478. The second drive magnet 472, also referred toherein as an output magnet, turns in response to rotations of a nutatingdisk C, which induces the first drive magnet 474 to rotate the rotors468. A photograph of a prototype generator assembly 462 is provided asFIG. 22.

The magnetic orientations of rotor magnets 466 are illustrated in FIGS.23 and 24. The eight permanent magnets 466 are approximately equallyspaced about each rotor 464, i.e., 45 degrees apart, and arranged sothat their polarity alternates. Thus, a magnet 466 a with its south polefacing the rotor 464 is followed around the disk perimeter by a magnet466 b with its north pole facing the stator 468. Further, the polarityof magnets on the top rotor 464 a and the bottom rotor 464 b areoriented in an opposing manner. Thus, a magnet 466 a on the top rotor464 a with its south pole facing the stator 468 is positioned directlyabove a magnet 466 c with its north pole facing the stator 468. Whenassembled, this orientation of permanent magnets 466 on the two rotors464 cause magnetic fields 480 to flow through adjacent coils 470 in thestator 468 and through the magnetically conductive plates 464 in themanner indicated by the dashed arrows in FIG. 24. In an embodiment, theflux density through the stator coils 470 is estimated to beapproximately 2473 Gauss or 0.2473 Tesla. A photograph of a prototyperotor 464 is provided in FIG. 25.

Further details regarding a design of an embodiment of the stator 468are presented in FIGS. 26-30. A photograph of a prototype coils 470 laidout in the orientation in which they can appear on the stator 468 ispresented in FIG. 26. As illustrated in FIG. 27 the eight coils 270 arespaced evenly about the perimeter of the stator 468, i.e., at 45 degreesapart. In an embodiment, the coils 470 are each approximately 0.5 inchin diameter and approximately 0.1 inch thick and include 400 wrapsexhibiting approximately 8 ohms resistance. In an embodiment, the coils470 are sandwiched between 0.015 inch thick (approximately) clearstyrene. In an embodiment, the stator 468 is approximately 2 inches indiameter so that it may fit within the housing 482 of a conventionalwater meter, such as the housing 482 shown in FIG. 28.

The winding orientations and electrical interconnections of the eightcoils 470 in the stator 468 are illustrated in FIGS. 29 and 30. FIG. 29illustrates how the eight magnets 466 in one rotor 464 can match up tothe eight coils 470 designated as A1-A4 and B1-B4. As FIGS. 29 and 30reveal, the coils are wired in series but interconnected so thatadjacent coils have opposite winding orientations so that the eightcoils have a single phase connection.

Current output from the generator can be rectified using a rectifiercircuit, an example embodiment of which is illustrated in FIG. 31. Inthis example two germanium diodes 492, 494 rectify current from thestator coils 466 with output voltage stored in buffer capacitors 496 and498.

Prototypes of the foregoing generator embodiments were tested andinstalled in two commercially available water meter housings,specifically a meter manufactured by Sensus and a meter manufactured byHersey. Results of this prototype testing are presented in the tablesprovided in FIG. 32. As shown in the tables in FIG. 32, the embodimentdescribed herein demonstrated output (>2 V) pole-to-pole voltage Vp-pand direct current voltage Vdc at low flow rates (1-2 GPM), and outputvoltage (>10 V) at moderate flow rates (5-10 GPM).

The measuring circuitry of the METER Mote 401 embodiment collects waterusage data, and may detect any back-flow occurrence, monitor waterpressure and upload the data to the central collection point. In anembodiment, the METER Mote 401 uses the MDA300 sensor board fromCrossbow Technologies which has the ability to monitor eight analoginputs, monitor and control 8 digital inputs or outputs and includes twocontact closure circuits. Rotation of the magnetic field generated bythe second drive magnet 472 (FIG. 21) can be sensed by Hall effectsensors 500, an example of which is shown in FIG. 33. When the Halleffect sensors 500 are positioned about the shaft 476 where the magneticfield of the second drive magnet 472 is present at two angles about theshaft, such as 45-90 degrees of offset as shown in FIG. 34, themicrocontroller 420 in the mote 404 can calculate the position of therotor, and thus count turns of the nutating disc. An example logic tablethat may be implemented within the microcontroller 420 is illustrated inFIG. 35. Using such logic, the microcontroller can incremented a binarycounter with each shaft rotation, and use the counter value to calculatewater flow. The logic table illustrated in FIG. 35 can also be used todetect rotation direction, and thus detect backflow.

In an embodiment, each METER Mote 401 is configured with a duty cycleconsisting of alternating periods of sleeping and activity. In order toconserve power most of the time the mote is sleeping. When the mote 404is awake it needs to perform several functions, including powermanagement, water meter readings and communication. The motemicrocontroller 420 can be configured via software to support thisfunctionality via a power management phase, a wakeup synchronizationphase, a meter reading phase and a communication phase. An exampleprocess flow for these functions and phases is provided in FIG. 36.

When each mote wakes up it checks its available power and decides whichpower source to use during that phase, step 550. At this time the motealso can change the charging cycle for the lithium battery. After thisphase the mote may enter a wakeup synchronization phase. This phase maybe implement because motes must wake up at roughly the same time,meaning that each mote's internal clock must be closely re-synchronizedwith the other motes in the system. At the start of the phase the basestation may issue a command to run a time synchronization protocol.Alternatively, the time synchronization process may be implemented afterdata has been transmitted as illustrated in FIG. 36 as step 558. In anembodiment, the synchronization protocol is based upon one of thestandard algorithms available in the TinyOS software release. TinyOS isa standard operating system for wireless sensor networks (WSN). Thisphase may take several minutes to complete. During this phase meshrouting paths may be established. The outcome of this phase is that allthe clocks can be synchronized with each other for several more dutycycles and mesh networking routes are established.

During the next phase each mote “reads its meter.” The meter readingconsists of the current value, and this value is time-stamped toindicate when the reading was performed. The time-stamped value is thenstored in local mote memory.

During the fourth phase the motes 404 prepare data packets, step 552,and start to communicate data back to the base station. As part of thisphase each mote may listen for a base station or collector 405 routingbeacon, step 554. Each mote 401 is responsible for sending in its ownvalue and for forwarding information received from other motes. Thisforwarding activity is part of the WSN mesh networking architecture. Inan embodiment, the motes 401 uses the TinyOS Multi-Hop Routing protocolfor mesh networking. This protocol allows data and control informationto be sent from the METER Mote system to the communications network.

A novel feature concerns techniques for data packet optimization. Atraditional approach for reporting sensing readings is to have eachpacket write its value into the packet, and then simply have eachintermediate sensor node forward that packet. However, in an environmentwith significant levels of interference frequent packet losses can besubstantially lower the success rate of each mote 404 reporting in. Inan embodiment these problems are overcome by allowing each mote 404 topiggyback the reports from other motes into its own report, step 556.This automatically increases the likelihood that at least one of themotes reports can make it back to the base station or collector 405.

Since each TinyOS packet has a limited amount of space, it is necessaryto compress the amount of data each mote 404 sends, since multiplereadings need to be contained in a single packet. This may be achievedusing several techniques. In an embodiment, a bitmap representation isused to signify from which mote 401 the data is coming from, and whatthe message is (status or alarm). Each bitmap contains space to signifynode id and type of message. The advantage of this embodiment is thatreports can become highly compressed. Further, each mote 401 can rapidlyadd its own values by simply performing bit level operations such as alogical AND. The piggyback operation is therefore performed at chiplevel speeds. Using a logical time stamping technique the time that thedata was sampled can be represented, thereby significantly lowering theamount of space required in each report data packet.

After data has been transmitted, each mote may reset it timer, step 558,if that process has not already been performed. With all functionscompleted, each mote can go back to sleep until the next scheduled wakeup, step 560.

The software architecture used to configure the mote microcontroller 420can use standard modular programming techniques. This approach allowsfuture implementations to easily incorporate greater functionality, suchas communications network to METER Mote 401 communication for additionalcontrol information, such as value shutoff, or protocols for securityand confidentiality.

The embodiments of the present inventions are not to be limited in scopeby the specific embodiments described herein. For example, although manyof the embodiments disclosed herein have been described in the contextof systems and methods for performing remote water meter monitoring,other embodiments, in addition to those described herein, will beapparent to those of ordinary skill in the art from the foregoingdescription and accompanying drawings. Thus, such modifications areintended to fall within the scope of the following appended claims.Further, although some of the embodiments of the present invention havebeen described herein in the context of a particular implementation in aparticular environment for a particular purpose, those of ordinary skillin the art will recognize that its usefulness is not limited thereto andthat the embodiments of the present inventions can be beneficiallyimplemented in any number of environments for any number of purposes.Many modifications to the embodiments described above can be madewithout departing from the spirit and scope of the invention.Accordingly, the claims set forth below should be construed in view ofthe full breath and spirit of the embodiments of the present inventionsas disclosed herein. Also, while the foregoing description includes manydetails and specificities, it is to be understood that these have beenincluded for purposes of explanation only, and are not to be interpretedas limitations of the present invention.

1. A method comprising: rotating a rotating device by a flow of water;rotating a drive magnet in response to the rotation of the rotatingdevice, wherein the rotation of the drive magnet generates a timevarying magnetic flux density; rotating a registration magnet inresponse to the time varying magnetic flux density; rotating a pair ofrotors with respect to a series of coils interposed between the pair ofrotors, the rotation being in response to the rotation of theregistration magnet, thereby generating an alternating current (AC) inthe series of coils; converting the alternating current (AC) to a directcurrent (DC); charging a first power storage device using the directcurrent (DC) and charging a second power storage device from the firstpower storage device; and monitoring voltage levels of the first powerstorage device and second power storage device and causing a transfer ofenergy from the first power storage device to the second power storagedevice in the event that the voltage level of the first power storagedevice is above a first threshold and the voltage level of the secondpower storage device is below a second threshold.
 2. The method of claim1 further comprising maintaining output voltage levels within aspecified range.
 3. The method of claim 1 wherein the registrationmagnet and drive magnet are magnetically coupled.
 4. The method of claim1 wherein each rotor comprises at least one magnetic pole.
 5. The methodof claim 1 wherein energy is harvested and stored in response to theflow of water on the rotating device.